<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		<select id="set" onchange="aa();">
			<option value ="">请选择网站</option>
			<option value ="https://www.baidu.com">百度</option>
			<option value ="https://www.163.com">网易</option>
			<option value ="https://www.taobao.com">淘宝</option>
		</select>
		
	</body>
	<script type="text/javascript">
		function aa()
		{
		var s1=document.getElementById('set').value;
		location.href=s1;
		}
	</script>
</html>
